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Saturday, November 12, 2016

Engine DISassembly (Part One)

After a bit of a hiatus, I began tearing down the engine I intend to hang on the front of the plane. I'll be using a 2180 Volkswagen engine, originally built for aircraft use by Hapi a number of years ago. When I received the engine, it was mostly assembled, but I wanted to tear it down, blueprint everything, and rebuild it myself so I know it's done right. Besides, it's hard to powder coat an engine block with stuff attached. So today I finally started yanking stuff off.

Engine on the stand, ready for disassembly:

First I pulled the intake manifolds and spark plugs. I'm working on this engine away from home, so I lack most of my tools and all the helpful things like oil drain pans... Therefore, I used an empty lemonade bottle to catch the old oil. Seemed to work.

I pulled the valve covers, then the valve train. Sure looks a lot simpler than any other engine I've taken apart.

Next step was to pull the head, which came off pretty easily, along with one of the cylinders. The other cylinder wasn't much trouble.

The pushrods and pushrod tubes fell right out as well, and I hung onto those for referencing when I reassemble. I'll probably replace them, along with a good deal of other hardware inside.

The left head valve train was shimmed about .122 off of the head.

The right side wasn't any more difficult than the left. Valve train shimmed .088 on the right side.

I'd have liked to do more, but a little research is in order. The pistons are held on by a large pin, and that pin is usually captured by E-clips or similar devices. Whoever assembled this engine most recently used Teflon blocks that ride against the cylinder wall instead. Nice idea in theory, but if they ever wear down, there wouldn't be anything holding the piston pin in place... which would mean a catastrophic failure. I also noticed that one of the Teflon "buttons" had picked up some debris and scored the cylinder wall with it... another thing that wouldn't happen with the right hardware. I'll have to take some measurements and decide whether I want to hone that cylinder or replace it.

This is where I left off today.

You can see the Teflon "buttons" in the picture below - they're the white circles on the sides of the pistons. I have no idea how to remove these, unless they're to be pressed out with the piston pins. Time for research.